Centripetal Compressor

ABSTRACT

Dual-action pistons positioned in cylinders that describe a translational movement in space are responsible for starting operation of the compressor. The advantage of this system is that the centripetal force is the only force responsible for the gas compression work, thereby resulting in a reduction in the power consumed as compared with conventional compressors.

OVERVIEW

Double-acting pistons placed in cylinders describing a translational motion in space are responsible for the principle of operation of the compressor. The advantages of this system is that the centripetal force is the sole responsible for the work of compression of gases, resulting thereby in a reduction in power consumption compared to traditional compressors.

DESCRIPTION Centripetal Compressor

The present patent of invention consists of two or more juxtaposed cylinders connected to a main axis, so as to bring balance to the system. The cylinders are put to rotate at a fixed speed, which is predetermined in design, describing a translational motion in space, and each cylinder has double acting free pistons, where the only force acting on the piston compression is caused by centripetal acceleration. Piston weight, diameter, rotation, and radius determines the working pressure of the machine.

State of the Art

At the State of the Art there is the following relationship to determine the work usable on the compression of a perfect gas, taking into account an isentropic transformation, according to Ennio Cruz da Costa in his book ‘Fisica Industrial, Termodinâmica—Part 1’, Editora Globo, Porto Alegre:

Lu = kRT 1 − k ∖ T 1 ${k{\frac{{RT}\; 1}{1 - k}\left\lbrack {\left( \frac{v\; 2}{v\; 1} \right)^{1 - k} - 1} \right\rbrack}} = {k{\frac{{RT}\; 1}{1 - k}\left\lbrack {\left( \frac{p\; 2}{p\; 1} \right)^{\frac{k - 1}{k}} - 1} \right\rbrack}}$

Such relationship is given to any type of compressor used, regardless of its construction, but taking into account the volume compressible up to a certain pressure.

The following are the compressors known at the State of the Art: piston, vane, screw. Roots, centrifugal, axial, diaphragm, and liquid ring. In these compressors, the mechanisms used to compress are connected directly to the shaft of either an electric or internal combustion engine always resulting in the same energy expenditure, taking into account the same gas flow. In the centripetal compressor claimed, such relationship ceases to exist because double-acting pistons do not have any mechanism to connect them to the shaft of an engine. The centripetal force that comes with the compressor rotation speed is the only force acting on the pistons causing compression of gases. This force causes no loss of power to the compressor, since it acts radially on the shaft at an angle of ninety degrees to the direction of rotation.

Operation

The rotation of the machine results in centripetal force, which in combination with the translational motion of the cylinder, produces the alternative movement of the pistons responsible for compression of gases. The centripetal force is the only force that does the work of compression of gases (F=m, V²/R). As the pistons are not mechanically triggered, the power required to compress the gas is nil. The power consumed to keep the machine in motion is generated by aerodynamic drag and by the friction of the bail bearings. To reduce aerodynamic drag, cylinders and machine are placed in drums where the confined gas is forced to rotate with the rotation of the system, reducing the power required to keep the compressor in operation (see picture on page 3/3).

Another advantage of this compressor is the elimination of the pressure switch since there is no gas consumption, the centripetal force acting on the pistons is balanced by the pressure of the system, preventing the pistons to compress beyond that pressure. Therefore, this compressor can operate without interruption since the compressive pressure will not exceed the working pressure for which the machine was designed.

Construction

Cylinders (1) containing double-acting free pistons (2) are placed in forks of the same radius (3), symmetrically opposed, fixed to a main shaft (4), which has is supported by fixed bearings (5) where fixed gears (6) are placed responsible for the translational motion of cylinders. The cylinders startup must be mounted so as to cause a translational motion onto them. The startup, such as described in the project, is triggered by drive chain (7). Each cylinder head has check valves that function as low-pressure gas admission and gas exhaust under pressure. Compressed gas flows through the exhaust valve to the ducts leading to the main shaft where the compressed gas is captured to be utilized (8) (see picture on page 1/3).

Construction Variables

The project hereby presented has only two cylinders since it consists of the basic mode of construction. The system can also be constructed with three or more cylinders opposed symmetrically in order to maintain the set balanced set, and the number of cylinders is determined according to each application's needs.

Another construction variable regards cylinder rotation during the translational motion. The rotation may or may not be zero, since the rotation of these cylinders in the translational motion can increase the volume capacity of the compressor. On the other hand, it may also limit the travel of the pistons by reducing compression time, thus reducing its capacity, In order to determine whether the cylinder will rotate, one must first decide on the piston travel.

Applications

It can replace any compressor where the main factor is to save energy. Its application can take place in various fields of human activity. Its main application, however, is generation of energy. Since the power to compress the air is reduced, the compressor can be coupled to a compressor air engine, thereby generating sufficient driving force for various applications.

Example of Calculation

Considering the weight of the pistons at 2.5 Kgf, the rotation operation at 2000 rpm for a 10 cm diameter piston, and a radius of 20 cm where cylinders will rotate, and considering that p-F/A, the force on the pistons will be 2235.7 Kgf, providing a working pressure of 28.5 Kgf/cm².

Equations

F=m. V²/R, where F is the centripetal force in Newton, m is the mass in Kg, V is the tangential velocity in m/s, and R is the radius in m.

p-F/A, where p is the pressure in Kgf/cm². F is the force in Kgf, and A is the area in cm².

BIBLIOGRAPHY

COSTA, Ennio Cruz da, Fisica industrial: termodinâmica—1 parte. Porto Alegre: Globe, 1971

SEARS;ZEMANSKY. Fisica volume 1; mecânica hidrodinâmica. Rio de Janeiro: Livros Técnicos e Científicos Editora S.A., 1978. 

1. (canceled)
 2. CENTRIPETAL COMPRESSOR, characterized by consisting of two opposing cylinders (1) connected to a main axis (4), these cylinders (1) performing a translational motion in space, each cylinder (1) having double-acting free-travel pistons (2), where the sole force to act on the compression of the pistons (2) is the centripetal force.
 3. CENTRIPETAL COMPRESSOR, characterized by consisting of cylinders (1) that perform a translational motion in space, and this translational motion of the cylinders (1) is responsible for the alternate movement of the pistons (2) that, combined with the sole force that acts on the pistons (2) compressing the gases, which is the centripetal force, produce the continuous movement of compression of the gases. 